Astrocyte Activation Research Articles

The activation of inflammatory responses in the brain is potentiated by over-expressing acetylcholinesterase in myeloid lineage of transgenic mice.

Acetylcholinesterase (AChE) has functions in neuroinflammation, beyond its classical role in neurotransmission. Understanding the role of AChE in neuroinflammation is of great significance, as it highlights the potential therapeutic targets for the treatment of neurodegenerative diseases. In an invitro study, the expression of AChE was up-regulated in lipopolysaccharide (LPS)-induced microglia/macrophage and contrarily potentiated the inflammatory responses via disturbing the cholinergic anti-inflammatory pathway (CAP). However, the regulation of AChE in neuroinflammation has not been revealed invivo yet. Here, we aim to uncover the inflammatory roles of microglial AChE in LPS-induced neuroinflammation by using the conditional AChE over-expression mouse model. AChE was specifically over-expressed in the myeloid cell linkage of mouse by applying CRISPR/cas9 combined with Cre-LoxP system. LPS was intraperitoneally injected into the mice to induce inflammation. The results showed that the inflammation, induced by LPS, was aggravated in the brain of transgenic mice having over-expression of AChE in microglia. The expressions of pro-inflammatory cytokines were robustly up-regulated in the brains of LPS-treated transgenic mice, as compared to the LPS-treated wildtypes. In parallel, the activations of microglia and astrocytes in hippocampus were enhanced significantly in AChE transgenic mice. Transcriptomics analysis further confirmed the severer inflammation in the transgenic mice than the wildtype after LPS administration. These findings shed light on the regulation of microglial AChE in neuroinflammation invivo for the first time, presenting another angle to understand the role of AChE in neurodegenerative diseases.

Lethal versus surviving sepsis phenotypes displayed a partly differential regional expression of neurotransmitters and inflammation and did not modify the blood–brain barrier permeability in female CLP mice

BackgroundSeptic encephalopathy is frequent but its pathophysiology is enigmatic. We studied expression of neurotransmitters, inflammation and integrity of the blood–brain barrier (BBB) in several brain regions during abdominal sepsis. We compared mice with either lethal or surviving phenotype in the first 4 sepsis days. Mature CD-1 females underwent cecal ligation and puncture (CLP). Body temperature (BT) was measured daily and predicted-to-die (within 24 h) mice (for P-DIE; BT < 28 °C) were sacrificed together (1:1 ratio) with mice predicted-to-survive (P-SUR; BT > 35 °C), and healthy controls (CON). Brains were dissected into neocortex, cerebellum, midbrain, medulla, striatum, hypothalamus and hippocampus.ResultsCLP mice showed an up to threefold rise of serotonin in the hippocampus, 5-hydroxyindoleacetic and homovanillic acid (HVA) in nearly all regions vs. CON. Compared to P-SUR, P-DIE mice showed a 1.7 to twofold rise of HVA (386 ng/g of tissue), dopamine (265 ng/g) and 3,4-Dihydroxyphenylacetic acid (DOPAC; 140 ng/g) in the hippocampus, hypothalamus and medulla (174, 156, 82 ng/g of tissue, respectively). CLP increased expression of TNFα, IL-1β and IL-6 mRNA by several folds in the midbrain, cerebellum and hippocampus versus CON. The same cytokines were further elevated in P-DIE vs P-SUR in the midbrain and cerebellum. Activation of astrocytes and microglia was robust across regions but remained typically phenotype independent. There was a similar influx of sodium fluorescein across the BBB in both P-DIE and P-SUR mice.ConclusionsCompared to survivors, the lethal phenotype induced a stronger deregulation of amine metabolism and cytokine expression in selected brain regions, but the BBB permeability remained similar regardless of the predicted outcome.

Adenosine-Dependent Arousal Induced by Astrocytes in a Brainstem Circuit.

Astrocytes play a crucial role in regulating sleep-wake behavior. However, how astrocytes govern a specific sleep-arousal circuit remains unknown. Here, the authors show that parafacial zone (PZ) astrocytes responded to sleep-wake cycles with state-differential Ca2+ activity, peaking during transitions from sleep to wakefulness. Using chemogenetic and optogenetic approaches, they find that activating PZ astrocytes elicited and sustained wakefulness by prolonging arousal episodes while impeding transitions from wakefulness to non-rapid eye movement (NREM) sleep. Activation of PZ astrocytes specially induced the elevation of extracellular adenosine through the ATP hydrolysis pathway but not equilibrative nucleoside transporter (ENT) mediated transportation. Strikingly, the rise in adenosine levels induced arousal by activating A1 receptors, suggesting a distinct role for adenosine in the PZ beyond its conventional sleep homeostasis modulation observed in the basal forebrain (BF) and cortex. Moreover, at the circuit level, PZ astrocyte activation induced arousal by suppressing the GABA release from the PZGABA neurons, which promote NREM sleep and project to the parabrachial nucleus (PB). Thus, their study unveils a distinctive arousal-promoting effect of astrocytes within the PZ through extracellular adenosine and elucidates the underlying mechanism at the neural circuit level.

Empagliflozin Attenuates High-Glucose-Induced Astrocyte Activation and Inflammation via NF-κB Pathway

Sodium-glucose cotransporter-2 (SGLT2) inhibitors regulate blood glucose levels in patients with type 2 diabetes mellitus and may also exert anti-inflammatory and anti-atherosclerotic effects by promoting M2 macrophage polarization. Although SGLT2 is expressed in brain regions that influence glucose balance and cognitive function, its roles in the central nervous system are unclear. This study investigated the effects of empagliflozin (EMPA), an SGLT2 inhibitor, on hypothalamic inflammation associated with metabolic diseases. Mice were subjected to a high-fat diet (HFD) for varying durations (3 d, 3 weeks, and 16 weeks) and treated with EMPA for 3 weeks (NFD, NFD + EMPA, HFD, HFD + EMPA; n = 5/group). EMPA regulated the expression of astrocyte markers and pro-inflammatory cytokine mRNA in the hypothalamus of HFD-induced mice, which was linked to regulation of the NF-κB pathway. Under hyperglycemic conditions, EMPA may mitigate hypothalamic inflammation by modulating astrocyte activation via the NF-κB pathway. Our findings demonstrated that EMPA possesses therapeutic potential beyond merely lowering blood glucose levels, opening new avenues for addressing inflammation and providing neuroprotection in metabolic disease management.

Neuropathology of Severe Depression in Long COVID-19 Infection; Possible Roles for Astrocytes, Creatine Kinase and Lactate Dehydrogenase Activity

Background: The incidence of depression has increased significantly during the COVID-19 pandemic. Some individuals infected with COVID-19 develop persistent neurological and neuropsychiatric symptoms approximately 12 weeks after the acute infection, a condition known as long COVID-19 syndrome. However, the underlying pathogenesis remains unclear. Glial fibrillary acidic protein (GFAP), creatine kinase (CK), and lactate dehydrogenase (LDH) are enzymes abundant in the central nervous system (CNS), playing important roles in neuronal energy homeostasis. Objectives: This study aimed to investigate the correlation between serum GFAP, CK, and LDH levels and depression in patients with long COVID-19 syndrome. Methods: This cross-sectional study involved 150 patients (75 males and 75 females). The Beck Depression Inventory-II (BDI-II) was used, along with standardized peripheral serum assessments. Serum GFAP, CK, and LDH levels were measured using customized direct ELISA. Data were matched by age and sex, and analyzed using Spearman non-parametric tests to assess the correlation between variables. Results: The serum level of GFAP was significantly higher in both males and females with severe depression compared to those with mild depression (282 ± 3 pg/mL, 280 ± 2.9 pg/mL, P = 0.001). The mean serum CK level was 239 ± 24.05 U/L in males and 142 ± 18.08 U/L in females (P &lt; 0.0001). Furthermore, a significant positive correlation was found between CK serum levels and Beck scores (r = 0.33, 95% CI = 0.176 to 0.469), with a similar pattern observed for LDH (r = 0.22, 95% CI = 0.042 to 0.358). GFAP, CK, and LDH levels were higher in male patients. Conclusions: This study identified potential neurobiological mechanisms in CNS-related long COVID syndrome, suggesting that elevated astrocyte activity, along with increased serum CK and LDH levels, may contribute to the neurobiological issues seen in depressed long COVID survivors. Men appeared to be more susceptible to these changes than women. Further research is essential.

The Neuroprotective Mechanisms of PPAR-γ: Inhibition of Microglia-Mediated Neuroinflammation and Oxidative Stress in a Neonatal Mouse Model of Hypoxic-Ischemic White Matter Injury.

Neuroinflammation and oxidative stress, mediated by microglial activation, hinder the development of oligodendrocytes (OLs) and delay myelination in preterm infants, leading to white matter injury (WMI) and long-term neurodevelopmental sequelae. Peroxisome proliferator-activated receptor gamma (PPAR-γ) has been reported to inhibit inflammation and oxidative stress via modulating microglial polarization in various central nervous system diseases. However, the relationship between PPAR-γ and microglial polarization in neonatal WMI is not well understood. Therefore, this study aimed to elucidate the role and mechanisms of PPAR-γ in preterm infants affected by WMI. In this study, an invivo hypoxia-ischemia (HI) induced brain WMI neonatal mouse model was established. The mice were administered intraperitoneally with either RSGI or GW9662 to activate or inhibit PPAR-γ, respectively. Additionally, an invitro oxygen-glucose deprivation (OGD) cell model was established and pretreated with pcDNA 3.1-PPAR-γ or si-PPAR-γ to overexpress or silence PPAR-γ, respectively. The neuroprotective effects of PPAR-γ were investigated invivo. Firstly, open field test, novel object recognization test, and beam-walking test were employed to assess the effects of PPAR-γ on neurobehavioral recovery. Furthermore, assessment of OLs loss and OL-maturation disorder, the number of myelinated axons, myelin thickness, synaptic deficit, activation of microglia and astrocyte, and blood-brain barrier (BBB) were used to evaluate the effects of PPAR-γ on pathological repair. The mechanisms of PPAR-γ were explored both invivo and invitro. Assessment of microglia polarization, inflammatory mediators, reactive oxygen species (ROS), MDA, and antioxidant enzymes was used to evaluate the anti-inflammatory and antioxidative effects of PPAR-γ activation. An assessment of HMGB1/NF-κB and NRF2/KEAP1 signaling pathway was conducted to clarify the mechanisms by which PPAR-γ influences HI-induced WMI in neonatal mice. Activation of PPAR-γ using RSGI significantly mitigated BBB disruption, promoted M2 polarization of microglia, inhibited activation of microglia and astrocytes, promoted OLs development, and enhanced myelination in HI-induced WMI. Conversely, inhibition of PPAR-γ using GW9662 further exacerbated the pathologic hallmark of WMI. Neurobehavioral tests revealed that neurological deficits were ameliorated by RSGI, while further aggravated by GW91662. In addition, activation of PPAR-γ significantly alleviated neuroinflammation and oxidative stress by suppressing HMGB1/NF-κB signaling pathway and activating NRF2 signaling pathway both invivo and invitro. Conversely, inhibition of PPAR-γ further exacerbated HI or OGD-induced neuroinflammation, oxidative stress via modulation of the same signaling pathway. Our findings suggest that PPAR-γ regulates microglial activation/polarization as well as subsequent neuroinflammation/oxidative stress via the HMGB1/NF-κB and NRF2/KEAP1 signaling pathway, thereby contributing to neuroprotection and amelioration of HI-induced WMI in neonatal mice.

Ginsenoside Rg1 Regulates the Activation of Astrocytes Through lncRNA-Malat1/miR-124-3p/Lamc1 Axis Driving PI3K/AKT Signaling Pathway, Promoting the Repair of Spinal Cord Injury.

To investigate the regulation of ginsenoside Rg1 on the PI3K/AKT pathway through the lncRNA-Malat1/miR-124-3p/ Laminin gamma1 (Lamc1) axis, activating astrocytes (As) to promote the repair of spinal cord injury (SCI). Bioinformatics analysis was used to predict miRNA targeting Lamc1 and lncRNA targeting miR-124-3p, which were then validated through a dual-luciferase assay. Following transfection, the relationships between Malat1, miR-124-3p, and Lamc1 expression levels were assessed by qRT-PCR and Western blot (WB). Immunofluorescence staining and immunohistochemistry were utilized to measure Lamc1 expression, while changes in cavity area were observed through hematoxylin-eosin (HE) staining. Basso-Beattie-Bresnahan (BBB) scale and footprint analysis were used to evaluate functional recovery. WB was performed to assess the expression of PI3K/AKT pathway-related protein. Rg1 was found to upregulate Malat1 expression, which in turn modulated the Malat1/miR-124-3p/Lamc1 axis. Furthermore, Rg1 activated the PI3K/Akt signaling pathway, significantly reducing the SCI cavity area and improving hind limb motor function. However, knockout of Malat1 hindered these effects, and inhibition of miR-124-3p reversed the silencing effects of Malat1. Rg1 can induce Malat1 expression to activate the Lamc1/PI3K/AKT signaling pathway by sponging with miR-124-3p, thereby regulating As activity to repair SCI.

Honey Enriched with Additives Alleviates Behavioral, Oxidative Stress, and Brain Alterations Induced by Heavy Metals and Imidacloprid in Zebrafish

Environmental concerns have consistently been a focal point for the scientific community. Pollution is a critical ecological issue that poses significant threats to human health and agricultural production. Contamination with heavy metals and pesticides is a considerable concern, a threat to the environment, and warrants special attention. In this study, we investigated the significant issues arising from sub-chronic exposure to imidacloprid (IMI), mercury (Hg), and cadmium (Cd), either alone or in combination, using zebrafish (Danio rerio) as an animal model. Additionally, we assessed the potential protective effects of polyfloral honey enriched with natural ingredients, also called honey formulation (HF), against the combined sub-chronic toxic effects of the three contaminants. The effects of IMI (0.5 mg·L−1), Hg (15 μg·L−1), and Cd (5 μg·L−1), both individually and in combination with HF (500 mg·L−1), on zebrafish were evaluated by quantifying acetylcholinesterase (AChE) activity, lipid peroxidation (MDA), various antioxidant enzyme activities like superoxide dismutase and glutathione peroxidase (SOD and GPx), 2D locomotor activity, social behavior, histological and immunohistochemical factors, and changes in body element concentrations. Our findings revealed that all concentrations of pollutants may disrupt social behavior, diminish swimming performances (measured by total distance traveled, inactivity, and swimming speed), and elevate oxidative stress (OS) biomarkers of SOD, GPx, and MDA in zebrafish over the 21-day administration period. Fish exposed to IMI and Hg + Cd + IMI displayed severe lesions and increased GFAP (Glial fibrillary acidic protein) and S100B (S100 calcium-binding protein B) protein expression in the optic tectum and cerebellum, conclusively indicating astrocyte activation and neurotoxic effects. Furthermore, PCNA (Proliferating cell nuclear antigen) staining revealed reduced cell proliferation in the IMI-exposed group, contrasting with intensified proliferation in the Hg + Cd group. The nervous system exhibited significant damage across all studied concentrations, confirming the observed behavioral changes. Moreover, HF supplementation significantly mitigated the toxicity induced by contaminants and reduced OS. Therefore, the exposure to chemical mixtures offers a more complete picture of adverse impacts on aquatic ecosystems and the supplementation with bioactive compounds can help to reduce the toxicity induced by exposure to environmental pollutants.

VEGFD/VEGFR3 signaling contributes to the dysfunction of the astrocyte IL-3/microglia IL-3Rα cross-talk and drives neuroinflammation in mouse ischemic stroke.

Astrocyte-derived IL-3 activates the corresponding receptor IL-3Rα in microglia. This cross-talk between astrocytes and microglia ameliorates the pathology of Alzheimer's disease in mice. In this study we investigated the role of IL-3/IL-3Rα cross-talk and its regulatory mechanisms in ischemic stroke. Ischemic stroke was induced in mice by intraluminal occlusion of the right middle cerebral artery (MCA) for 60 min followed by reperfusion (I/R). Human astrocytes or microglia subjected to oxygen-glucose deprivation and reoxygenation (OGD/Re) were used as in vitro models of brain ischemia. We showed that both I/R and OGD/Re significantly induced decreases in astrocytic IL-3 and microglial IL-3Rα protein levels, accompanied by pro-inflammatory activation of A1-type astrocytes and M1-type microglia. Importantly, astrocyte-derived VEGFD acting on VEGFR3 of astrocytes and microglia contributed to the cross-talk dysfunction and pro-inflammatory activation of the two glial cells, thereby mediating neuronal cell damage. By using metabolomics and multiple biochemical approaches, we demonstrated that IL-3 supplementation to microglia reversed OGD/Re-induced lipid metabolic reprogramming evidenced by upregulated expression of CPT1A, a rate-limiting enzyme for the mitochondrial β-oxidation, and increased levels of glycerophospholipids, the major components of cellular membranes, causing reduced accumulation of lipid droplets, thus reduced pro-inflammatory activation and necrosis, as well as increased phagocytosis of microglia. Notably, exogenous IL-3 and the VEGFR antagonist axitinib reestablished the cross-talk of IL-3/IL-3Rα, improving microglial lipid metabolic levels via upregulation of CPT1A, restoring microglial phagocytotic function and attenuating microglial pro-inflammatory activation, ultimately contributing to brain recovery from I/R insult. Our results demonstrate that VEGFD/VEGFR3 signaling contributes to the dysfunction of the astrocyte IL-3/microglia IL-3Rα cross-talk and drives pro-inflammatory activation, causing lipid metabolic reprogramming of microglia. These insights suggest VEGFR3 antagonism or restoring IL-3 levels as a potential therapeutic strategy for ischemic stroke.

Elevated circulating levels of GFAP associated with reduced volumes in hippocampal subregions linked to mild cognitive impairment among community-dwelling elderly individuals

ObjectiveCerebrospinal fluid biomarkers are challenging to use for diagnosing mild cognitive impairment (MCI) in large populations, and there is an urgent need for new blood biomarkers. The aim of this study is to investigate whether astrocyte activation is correlated with hippocampal atrophy, and to assess the potential of glial fibrillary acidic protein (GFAP) as a biomarker for diagnosing MCI among community-dwelling older individuals.MethodsThis cross-sectional study included 107 older adults. The levels of GFAP in serum were measured, and the volumetric assessment of gray matter within hippocampal subregions was conducted using Voxel-Based Morphometry (VBM). The relationship between hippocampal subregion volume and blood biomarkers were analyzed using partial correlation. The effectiveness of blood biomarkers in differentiating MCI was assessed using a receiver operating characteristic (ROC) curve.ResultsWe found that serum GFAP levels were significantly elevated in the MCI group compared to the cognitively normal (CN) group. Additionally, individuals with MCI exhibited a reduction gray matter volume in specific hippocampal subregions. Notably, the right dentate gyrus (DG) and right cornu ammonis (CA) subregions were found to be effective for distinguishing MCI patients from CN individuals. Serum levels of GFAP demonstrate a sensitivity of 65.9% and a specificity of 75.6% in differentiating patients with MCI from CN individuals.ConclusionSpecific atrophy within hippocampal subregions has been observed in the brains of community-dwelling elderly individuals. Elevated levels of circulating GFAP may serve as a sensitive peripheral biomarker indicative of hippocampal-specific cognitive alterations in patients with MCI.

Morphine self-administration is inhibited by the antioxidant N-acetylcysteine and the anti-inflammatory ibudilast; an effect enhanced by their co-administration.

The treatment of opioid addiction mainly involves the medical administration of methadone or other opioids, aimed at gradually reducing dependence and, consequently, the need for illicit opioid procurement. Thus, initiating opioid maintenance therapy with a lower level of dependence would be advantageous. There is compelling evidence indicating that opioids induce brain oxidative stress and associated glial activation, resulting in the dysregulation of glutamatergic homeostasis, which perpetuates drug intake. The present study aimed to determine whether inhibiting oxidative stress and/or neuroinflammation reduces morphine self-administration in an animal model of opioid dependence. Morphine dependence, assessed as voluntary morphine self-administration, was evaluated in Wistar-derived UChB rats. Following an extended period of morphine self-administration, animals were administered either the antioxidant N-acetylcysteine (NAC; 40 mg/kg/day), the anti-inflammatory ibudilast (7.5 mg/kg/day) or the combination of both agents. Oxidative stress and neuroinflammation were evaluated in the hippocampus, a region involved in drug recall that feeds into the nucleus accumbens, where the levels of the glutamate transporters GLT-1 and xCT were further assessed. Daily administration of either NAC or ibudilast led to a mild reduction in voluntary morphine intake, while the co-administration of both therapeutic agents resulted in a marked inhibition (-57%) of morphine self-administration. The administration of NAC or ibudilast markedly reduced both the oxidative stress induced by chronic morphine intake and the activation of microglia and astrocytes in the hippocampus. However, only the combined administration of NAC + ibudilast was able to restore the normal levels of the glutamate transporter GLT-1 in the nucleus accumbens. Separate or joint administration of an antioxidant and anti-inflammatory agent reduced voluntary opioid intake, which could have translational value for the treatment of opioid use disorders, particularly in settings where the continued maintenance of oral opioids is a therapeutic option.

Abnormal outer and inner retina in a mouse model of Huntington’s disease with age

Huntington’s disease (HD) is a progressive neurodegenerative disorder characterized by motor dysfunction and cognitive decline. While retinal abnormalities have been documented in some HD patients and animal models, the nature of these abnormalities—specifically whether they originate in the inner or outer retina—remains unclear, particularly regarding their progression with age. This study investigates the retinal structure and function in HD transgenic mice (R6/1) compared to C57BL/6 J control mice at 2, 4, and 6 months of age, encompassing both pre-symptomatic and symptomatic stages of HD. Pathological assessments of the striatum and evaluations of motor function confirmed significant HD-related alterations in R6/1 mice at 6 months. Visual function was subsequently analyzed, accompanied by immunofluorescent staining of retinal and optic nerve tissues over time. Our findings revealed that R6/1 mice exhibited pronounced HD symptoms at 6 months, characterized by neuronal loss in the striatum and impaired locomotor abilities. Functionally, visual acuity declined at 6 months, while retinal light responses began to deteriorate by 4 months. Structurally, R6/1 mice demonstrated a global reduction in cone opsin expression as early as 2 months, with a decrease in rhodopsin levels at 4 months, alongside a thinner retinal structure compared to controls. Notably, rod bipolar cell populations were decreased at 6 months, exhibiting shorter dendritic branches and reduced synaptic connections with photoreceptors in the outer retina. Additionally, ganglion cell numbers in the inner retina decreased at 6 months, accompanied by aberrant neural fibers in the optic nerve. Microglial activation was evident at 4 months, while astrocytic activation was observed at 6 months. Aggregates of mutant huntingtin (mHTT) were first detected in the ganglion cell layer and optic nerve at 2 months, subsequently disseminating throughout all retinal layers with advancing age. These results indicate that retinal pathology in R6/1 mice manifests earlier in the outer retina than in the inner retina, which does not align with the progression of mHTT aggregation. Consequently, the R6/1 mouse retina may serve as a more effective model for elucidating the mechanisms underlying HD and evaluating potential therapeutic strategies, rather than functioning as an early diagnostic tool for the disease.

The Gut-Brain Axis and Neuroinflammation in Traumatic Brain Injury.

Traumatic brain injury (TBI) is a major global disability and mortality cause, with the gut-brain axis playing a crucial role in its pathophysiology. Neuroinflammation, triggered by microglia and astrocytes, contributes to neuronal damage and cognitive impairment. This paper aims to explore the relationship between the gut-brain axis and neuroinflammation in TBI and its potential implications for therapeutic interventions. A comprehensive review of the literature was conducted using PubMed, MEDLINE, and Google Scholar databases. Studies investigating the gut-brain axis, neuroinflammation, and TBI were included. Evidence suggests that TBI disrupts the gut-brain axis, leading to alterations in gut microbiota composition, intestinal permeability, and immune responses. These gut-related changes promote the activation of microglia and astrocytes in the central nervous system, contributing to neuroinflammation and neuronal damage. Conversely, interventions that modulate gut microbiota or reduce intestinal permeability have been shown to attenuate neuroinflammation and improve cognitive outcomes in TBI models. The gut-brain axis plays a significant role in the pathogenesis of neuroinflammation following TBI. Targeting the gut-brain axis through interventions that restore gut homeostasis and reduce intestinal permeability holds promise as a novel therapeutic strategy for mitigating neuroinflammation and improving cognitive function in TBI patients. Further research is needed to elucidate the specific mechanisms involved and to develop effective therapies based on this understanding.

Necrostatin-1 as a Potential Anticonvulsant: Insights from Zebrafish Larvae Model of PTZ-Induced Seizures.

Epilepsy is a common neurological disorder affecting around 70 million people worldwide. Despite significant research and advancements in pharmaceutical therapies, the exact mechanisms underlying epileptogenesis remain unclear. As a result, current antiepileptic drug treatments are ineffective for approximately 30% of patients, providing only symptomatic relief. The epileptic process is influenced by the signaling of tumor necrosis factor alpha (TNFα), which affects neuronal excitability. The TNFα/TNFR1 signaling pathway and the role of RIPK1 in initiating inflammatory cell death pathways are well studied in human disorders. Dysregulation of RIPK1 is linked to inflammation and neurodegenerative diseases. Necrostatin-1 (Nec-1) selectively inhibits RIPK1 in various pathological conditions. The current study aimed to investigate the anticonvulsant properties of Nec-1 (a selective RIPK1 inhibitor) in PTZ-induced seizures in zebrafish larvae. Before the onset of seizures, zebrafish were treated with Nec-1 (15µM) for 24h at 6days post-fertilization (dpf), followed by exposure to 15mM of PTZ for 30min. Behavioral assessments were conducted to observe changes in locomotor activity. Additionally, c-Fos expression was measuredas an indicator of neuronal activation and analyzed mRNA levels of the astrocyte activation marker (GFAP) along with various inflammatory cytokines. Western blot analysis was conducted to evaluate GABAA receptor expression. Pretreatment with Nec-1 restored normal behavior and reversed the expression of c-Fos in zebrafish larvae induced by PTZ. Additionally, Nec-1 reduced the elevated mRNA expression of inflammatory cytokines and significantly suppressed TNF/TNFR1 signaling, thereby inhibiting the enhanced internalization of GABAA receptors. Our findings indicate that Nec-1 reduced the severity of PTZ-induced seizures in zebrafish by regulating behavior changes, suppressing inflammatory mediators, and enhancing the expression of GABAA receptors, suggesting potential anticonvulsant properties.

Zinc signaling controls astrocyte-dependent synapse modulation via the PAF receptor pathway.

Astrocytes are important regulators of neuronal development and activity. Their activation plays a key role in the response to many central nervous system (CNS) pathologies. However, reactive astrocytes are a double-edged sword as their chronic or excessive activation may negatively impact CNS physiology, for example, via abnormal modulation of synaptogenesis and synapse function. Accordingly, astrocyte activation has been linked to neurodegenerative and neurodevelopmental disorders. Therefore, the attenuation of astrocyte activation may be an important approach for preventing and treating these disorders. Since zinc deficiency has been consistently linked to increased pro-inflammatory signaling, we aimed to identify cellular zinc-dependent signaling pathways that may lead to astrocyte activation using techniques such as immunocytochemistry and protein biochemistry to detect astrocyte GFAP expression, fluorescent imaging to detect oxidative stress levels in activated astrocytes, cytokine profiling, and analysis of primary neurons subjected to astrocyte secretomes. Our results reveal a so far not well-described pathway in astrocytes, the platelet activation factor receptor (PAFR) pathway, as a critical zinc-dependent signaling pathway that is sufficient to control astrocyte reactivity. Low zinc levels activate PAFR signaling-driven crosstalk between astrocytes and neurons, which alters excitatory synapse formation during development in a PAFR-dependent manner. We conclude that zinc is a crucial signaling ion involved in astrocyte activation and an important dietary factor that controls astrocytic pro-inflammatory processes. Thus, targeting zinc homeostasis may be an important approach in several neuroinflammatory conditions.

Safety of a Medicinal Product Based on Human Glial Progenitor Cells: A Pilot Study of Retrobulbar Administration in C57BL/6J Mice

INTRODUCTION. Stem cell therapy is a promising treatment method for various diseases and injuries, but its safety has yet to be determined. Therefore, studying the safety of administering a xenogeneic cell-based medicinal product (CBMP) into the retro-orbital venous sinus is essential for developing protocols for further studies of potential medicinal products for neurological conditions.AIM. The aim of the study was to determine the optimal dose of a CBMP derived from glial progenitor cells (GPCs) and to evaluate its safety during retrobulbar administration in C57BL/6J mice.MATERIALS AND METHODS. GPCs were derived from human induced pluripotent stem cells by stepwise differentiation and cultured in DMEM/F12 supplemented with epidermal growth factor and ciliary neurotrophic factor. Matrigel was used as a substrate. GPCs were injected into the retro-orbital venous sinus of male C57BL/6J mice under isoflurane anaesthesia once a week for two months. The study analysed changes in biochemical blood parameters and behaviour. The quantities of activated astrocytes and glial cells were determined by postmortem immunohistochemical staining.RESULTS. The administration of GPCs at a dose of 500×103 cells/mouse, which was selected using literature data, induced an increase in the plasma levels of ala nine aminotransferase and aspartate aminotransferase. This could indicate cell damage and the development of inflammatory reactions. At doses reduced to one-third the initial GPC concentration or lower, the biochemical blood parameters of the treatment groups did not differ significantly from those of the control group. There were no significant differences in neuroinflammatory markers between the groups receiving GPCs at different doses, except for an increase in astrocyte activation at a dose of 150×103 cells/mouse, which could potentially indicate inflammatory processes in the brain. The study detected no pathological changes in the brain or cell damage markers in the blood of mice after retrobulbar GPC injections of 15×103 or 50×103 cells/mouse.CONCLUSIONS. The study results indicate that long-term therapy with GPCs is potentially safe for mice if the dose is optimal. The authors suggest using the optimal doses and the administration route established in this study for further research into the safety of intravenous administration of CBMPs for neurological conditions.

Retraction: Tregs depletion aggravates activation of astrocytes by modulating IL-10/GXP4 following cerebral infarction

Retraction: Tregs depletion aggravates activation of astrocytes by modulating IL-10/GXP4 following cerebral infarction

Neuroprotective Effects of Heinsia crinita and Coconut Water in a Scopolamine-Induced Alzheimer's Model in Albino Rats: Biochemical Changes, Cellular Health, and Neuronal Activity

Aim: This study aimed to investigate the potential therapeutic effects of Heinsia Crinita and Tender Coconut water (TCW) on Alzheimer's disease, focusing on their phytochemical composition, antioxidant activity, and anti-inflammatory effects. The study aimed to identify potential therapeutic agents for Alzheimer's disease and contribute to the development of more effective and natural treatments for this devastating disorder. Study Design: The study used a randomized controlled trial design, with six groups: negative control (Group A), positive control (Group B), Donepezil-treated group (Group C), TCW-treated group (Group D), Heinsia Crinita-treated group (Group E) and TCW + Heinsia Crinita-treated group (Group F). Place and Duration of Study: The study was carried out in the University of Calabar, between February 2022 and January 2024. Methods: About 30 rats were used for the work. Alzheimer's disease-like neurotoxicity and neurodegeneration was inducee in 25 rats using scopolamine; 1.0 mg/kg, intraperitoneally (i.p.) and then treated with the respective interventions; TCW (2ml/kgBW) and Heinsia Crinita (500mg/kgBW). Histological analysis of the hippocampal tissue was performed using Hematoxylin and Eosin stain and Glial Fibrillary Acid Protein (GFAP) stain. Biochemical assays were conducted to determine Malondialdehyde (MDA) levels and glutathione peroxidase (GPx) activity. Results: The results of the study showed that Heinsia Crinita may provide greater health benefits than Tender Coconut water due to its higher concentrations of bioactive compounds like alkaloids, flavonoids, and saponins, enhancing its medicinal properties, particularly its antioxidant and anti-inflammatory effects. Scopolamine induced histomorphological, immunochemical, and biochemical alterations. When combined with Tender Coconut water, Heinsia crinita (Group F) shows improved efficacy in reducing inflammation, cellular damage, and oxidative stress compared to Tender Coconut water alone. This combination is also as effective as Donepezil (Group C) in alleviating immunochemical alterations in a scopolamine-induced Alzheimer's model in Wistar rats, marked by reduced astrocyte activation, lower malondialdehyde (MDA) levels, and increased glutathione peroxidase (GPx) activity p &lt; 0.05. Conclusion: This study suggest that the combination of Heinsia Crinita and Tender Coconut water may serve as a promising therapeutic approach for addressing neurodegenerative conditions like Alzheimer's disease. The enhanced medicinal properties of Heinsia Crinita, particularly its ability to reduce oxidative stress and inflammation, coupled with the nutritional benefits of tender coconut water, could provide a synergistic effect that supports neuronal health and mitigates disease progression. This finding highlights the potential for natural products to be integrated into traditional medicine and modern therapeutic strategies.

Current insights into apolipoprotein E and the immune response in Alzheimer's disease.

Alzheimer's disease (AD) is a progressive neurological disorder and the most common cause of dementia. Genetic analyses identified apolipoprotein E (APOE) as the strongest genetic risk for late-onset AD. Studies have shown that ApoE modulates AD pathogenesis in part by influencing amyloid-β (Aβ) deposition. However, ApoE also appears to regulate elements of AD via regulation of innate immune response, especially through microglial and astrocyte activation. In model systems, it also regulates changes in T-cells. This review focuses on the key findings that have advanced our understanding of the role of ApoE in the pathogenesis of AD and the current view of innate immune response regulated by ApoE in AD, while discussing open questions and areas for future research.

Theta-burst transcranial magnetic stimulation attenuates chronic ischemic demyelination and vascular cognitive impairment in mice

Vascular cognitive impairment and dementia (VCID) is mainly caused by chronic cerebral hypoperfusion and subsequent white matter lesions. Noninvasive transcranial magnetic stimulation has been utilized in treating various neurological disorders. However, the function of theta-burst transcranial magnetic stimulation on VCID remains to be defined. We utilized 4-week bilateral carotid artery stenosis model of male mice to mimic VCID. Intermittent theta-burst stimulation (iTBS) or consecutive theta-burst stimulation (cTBS) was administered for 14 consecutive days. Through luxol fast blue staining, electron microscopy and immunofluorescence, we found that iTBS, not cTBS, significantly improved demyelination, axonal damage and β-amyloid deposition, without affecting cerebral blood flow in VCID mice. At cellular levels, iTBS rescued the loss of mature oligodendrocytes, promoted precursor cell differentiation, and inhibited pro-inflammatory activation of astrocytes and microglia. Notably, iTBS attenuated cognitive deterioration in both short-term retention and long-term spatial memory of VCID mice as indicated by serial neurobehavioral tests. To explore the molecular involvement of iTBS, mRNA sequencing was carried out. By real-time PCR and combined RNA fluorescence in situ hybridization with immunofluorescence, iTBS was confirmed to increase Rxrg expression specifically in mature oligodendrocytes. Collectively, iTBS could ameliorate vascular cognitive dysfunction, probably via mitigating white matter lesions and neuroinflammation in the corpus callosum. Rxrg signaling in mature oligodendrocytes, which was increased by iTBS, might be a potential target for VCID treatment.